William gave you all the census info so I won’t duplicate it.There is a Website for the PEI archives and there you can find the birth/baptisms for All of Ellen/Helen and John’s children.(I am just giving you birth dates, not baptisms)
Barbe, Dec. 12, 1868 Eustache July 15, 1871 Madeleine Jan. 12, 1872 Mary JaneJan. 2, 1874 Bridget Ellen May 4, 1875 Mary Elizabeth April 30, 1877 May Jane Feb. 30, 1979 Jean June 15, 1882 Emelie Aug. 20, 1885 CharlesJuly 2, 1887
I could not find Emma or Paul in the database
I found some trees at ancestry.com which show John as Jean ACOIN and some which show him as Jean AUCOIN DIT WEDGEso not sure if they are right.
They also show marriage for Jean AUCOIN and Helen BLAQUIERE as Feb. 25, 1867 but none of them show sources. They also show Jean’s birth as Oct. 1, 1835 and there is a Jean AUCOIN in the database mentioned above – who has that birth date Parents A. ARSENAULT AND JEAN AUCOIN
Helen’s parents shown in the trees as CHARLES BLAQUIERE/BLACQUIERE AND BARBE GALLANT and Helen’s birth as May 18, 1845
The database has a Eiln BLAQUIERE born May 18, 1845 to those parents
The databases do not include marriages though but you could try writing to the PEI Public archives and Records Office as they are supposed to have some marriage records there, just not online.